bench.jl

using FFTW
n = 128
m = 5
X = randn(ComplexF64, n, n, n, m)
p = plan_fft!(X, (1, 2, 3))

Y = copy(X)

GC.gc()
GC.enable(false)

@time mul!(X, p, X)
@time mul!(X, p, X)
@time mul!(X, p, X)
println()
@time copy(X)
@time copy(X)
@time copy(X)
println()
@time zero(X)
@time zero(X)
@time zero(X)
println()
@time (Y = similar(X); fill!(Y, 0))
@time (Y = similar(X); fill!(Y, 0))
@time (Y = similar(X); fill!(Y, 0))
println()
@time copy!(Y, X)
@time copy!(Y, X)
@time copy!(Y, X)
println()
@time fill!(Y, 0)
@time fill!(Y, 0)
@time fill!(Y, 0)

GC.enable(true)